I have 60db with Lyra Skala (same .5mv) and it's outstanding.
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Some 60db phono stages will be fine, and others will not be.
Assuming that your line stage preamp provides a reasonable amount of gain, say 10db or more, and that your power amp has a typical sensitivity number, say 1.5 volts or less (unbalanced), you'll have enough gain. The more important question is the signal-to-noise ratio (s/n) provided by the phono stage. If that is not particularly good, you may wind up with objectionable hiss levels.
I couldn't find a s/n spec for the Fosgate Signature. The last paragraph on this page, from the TAS review, is encouraging though.
However I would suggest that what would constitute the "pertinent experience" you are looking for would be specific experience with the Fosgate. Perhaps someone using it with a 0.8 to 1.0 mv cartridge could try turning up their volume control to a level around 6db higher than they would normally listen at, and indicate what kind of hiss levels result while no music is being played.
What Al says makes sense. My phono pre is an ARC PH-7 which has 57.5 db of gain. The noise and hum stat is 70db. My line-stage is an ARC Ref-5 which has 12 db of gain if the XLR output is used, which it is in my case. The noise and hum stat is 109db. So total gain is almost 70db.
ARC advised me that I should not use a cartridge that produces less than .5mV of gain, and more would be better. So far, I have used high output MC and MM cartridges that produce more than 2mV so I can't personally vouch that .5mV is ok, but what I can say is that what Al says is consistent with the advice ARC gave me.
I would be cautious extrapolating from experience with the Linto. In addition to the fact that it is solid state, as indicated in its manual it is a very unusual design in that it drives the input signals directly into the amplifying transistors, with no loading network (the intent being to reduce noise); and it has an unusually high input capacitance of 4700pf (which may further reduce noise). The Fosgate differs in all of those respects, and also provides 4db less gain.
Regarding downstream compatibility, I will at first be feeding output of the phono amp into a Marantz AV7005 pre/pro. I could not find a line stage gain spec for this unit. Input sensitivity is claimed to be 200 mV / 47k-Ohm and pre-out is 1.2 V unbalanced, 2.4 V balanced I dont know how to translate that into gain. Ill be using the balanced output into a Parasound Halo A51, sensitivity = 1 V for 28.28 V. Down the road, barring insolvency, Ill insert a nice preamp with a threatre bypass mode into the stream, probably a Parasound JC-2 (gain 14dB) or a Rogue Audio Athena (gain 15dB balanced.)
Dave, those numbers all seem reasonable to me, and I don't see any issues with them.
Gain, btw, is calculated as 20log(Vout/Vin). For the AV7005, that would be 21.6db for the balanced outputs, and 15.6db for the unbalanced outputs.
Again, as I see it the main spec-related question in this case is s/n performance, not gain.
Al, thanks! Since the reviews I have read of the Fosgate, albeit sans actual measurements, consistently cite quietness for its genre. So far, then, so good! If I've read it once, I've read a thousand times in this forum and others, that meaningfully auditioning of high-end gear, especially for vinyl playback, is a very tough thing to pull off. All the more so for me, who lives hundreds of miles from a major city.
HI Dave - the phono stage should be fine, BUT - I have tried both the Delos and Kleos in my JMW arm ( SuperScoutmaster) and have not been impressed with either. I have tried the same cartridges in gimbled tonearms and they are excellent, so I have to attribute my results with some sort of incompatibility with a unipivot ( or this particular unipivot) arm. I do know what I am doing with setup and have all the requisite tools to check and recheck the setup. Work with a dealer that offers you some recourse in case you do not care for the results on your Classic, which is an excellent table, by the way.
Bifwynne, like you, I ended up with and am very happy with the Soundsmith VPI Zephyr cartridge. Prior to the Lyra carts, I have been using a Benz Ruby 3 which I really liked but which finally wore out. The Zephyr has the best channel separation and is the least affected by surface noise of any cartridge that I have ever used and is a lot less expensive than the other cartridges as well. Instrument timber and tonality is on par with the very best also.
Regarding suitable gain of a phono stage for the Kleos, I'd normally suggest 63dB or more, although if you have a high-gain preamp, power amp, or quite efficient speakers, 60dB may be enough (as J. Frech has suggested).
For lower-gain phono stages, I'd suggest the higher-output Delos, which is a better-sounding, better-performing cartridge than the more expensive Helikon (now discontinued).
One thing worth mentioning is that the phono stage design is very important to the perception of surface noise - a phono stage designed to have good high-frequency overload margin and linear, low-distortion in the ultrasonic region will usually sound quieter.
As I mentioned to your question in the other thread, I have used or set up the Kleos on various unipivots like Grahams, Audiocrafts, Moerchs, Spiral Grooves and whatnot, but haven't encountered any problems that I could pin down to unipivots as a category.
kind regards, jonathan carr